The Cytochrome P450 (P450) superfamily of enzymes is one of three enzyme systems which metabolize the fatty acid arachadonic acid (AA) to regulators of vascular tone. P450 enzymes are monooxygenase enzymes which require several co-factors such as nicotinamide adenine dinucleotide phosphate (NADPH) and P450 reductase. There are over 200 known genes which encode P450s. Epoxygenases are those P450s which metabolize AA to epoxyeicosatrienoic acid (EETs) and omega-hydroxylases are those P450s which produce 19- and 20- hydroxyeicosatetraenoic acids (19- and 20-HETE). As well as fatty acid metabolism, P450s also metabolize many drugs and toxins. Cytochrome P450 3A4 is abundantly expressed in liver and small intestine and is inducible by barbiturates, glucocorticoids and rifampicin.

Phase 1 drug metabolism is catalyzed by two groups of monooxygenases, the cytochrome P450s (CYPs) and the flavin monooxygenases (FMOs). Both CYPs and FMOs are localized in the endoplasmic reticulum. Collectively, these enzymes catalyze the oxidation of a very broad range of substrates. Both classes are dependent on NADPH as a source of electrons, but the two classes exhibit significant differences in mechanism and substrate specificity.

May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.